DRV8305-Q1 Automotive 3-Phase Brushless DC Gate Driver

Hello, my name is Andrew Leverette. And I'm with Texas Instruments' motor drive business unit. And today, I'd like to introduce DRV8305-Q1, our automotive three-phase brushless DC gate drive.
The DRV8305-Q1 comes with a very robust performance meeting many on automotive standards and needs-- more specifically, supply operation down to 4.4 volts for start-stop or cold-crank situations and up to 45 volts for battery-load dump situations, smart gate drive for full MOSFET protection, 150C ambient operation to support Grade 0 requirements, and full protection with reporting via SPI port.
The DRV8305-Q1 is also highly integrated with an integrated LDO, watchdog, and three current sense amps. Along with high performance and integration, the DRV8305-Q1 is highly configurable via the SPI port, allowing configuration of slew rate or gate drive current, sense amp gain and reference, and dead time, to name a few.
The DRV8305-Q1 comes with two temperature profile options specified under the AEC-Q100 standard, Grade 0 for minus 40 degree Celsius to 150 degrees Celsius ambient operation, and Grade 1 for minus 40 degrees Celsius to 125 degrees Celsius ambient operation. For Grade 0 operation, the maximum junction temperature is extended to 175 degrees Celsius, while for Grade 1, the maximum junction temperature is limited to 150 degrees Celsius.
To further understand the level of integration of this device, let's take a look at the block diagram. As mentioned previously, this device integrates an LDO, watchdog, and three sense amps. It also employs drivers whose current can be adjusted via SPI from 10 milliamps to 1.25 amps, eliminating the need for external gate resistors. The DRV8305-Q1 also eliminates the need for an external boost converter or a large capacitor to sustain operation during cold cranks by employing a tripler charge pump. This charge pump enables operation down to 4.4 volts with more than enough gate drive to sustain the performance.
In automotive, there are many starting profile specifications, one of the more popular being ISO 16750-2, where the voltage can go as low as 4.5 volts before settling to its typical value. We simulated this exact profile in the lab and observed the gate drive voltage of the DRV8305-Q1. As you can see, there is only a slight dip in the gate drive voltage while sustaining full-pulse operation.
Along with integration, the DRV8305-Q1 is highly configurable through SPI, optimizing or eliminating MCU resources. One, three, or six PWM inputs can be chosen to accommodate several control methods from sensor trapezoidal to sensor [INAUDIBLE] sinusoidal. The gate current and slew rate can be configured for optimizing EMI in motor performance.
Dead time can be adjusted to optimize external FET protection. And various features of the three current sense amps can be configured. Let's take a quick look at those features.
Through the SPI bus, the gain of the sense amps have four different configurations-- 10, 20, 40, and 80, while the output bias voltage have three as a divisor of VREG. Most importantly, the sense amps can be calibrated to minimize drift and offset. As shown in this waveform, the blanking time can be extended to sample a settled and accurate voltage.
The DRV8305-Q1 is fully protected with enhanced fault indication and reporting through the SPI bus. Key protection features are over temperature, PVDD, or battery overvoltage and undervoltage, brownout indication, watchdog, minimum built-in dead time, external VDS monitors with programmable over VDS levels, and multilevel shoot through protection, or smart gate drive.
The smart gate drive architecture uses a state machine to prevent turn on of [INAUDIBLE] from fast slewing phase nodes, or in other DV/DT turn on. When the DRV8305-Q1 begins to activate the high-side gates by sourcing the programmed current or I drive, the low-side gate driver pulls very hard on the low-side gate to keep the potentially capacitive coupled high-side voltage from activating the low-side gate and causing shoot through.
Here's a scope plot of this happening, where you have a very fast slewing input in blue causing a turn on the high-side VGS in yellow. As you can see, the low-side VGS attempts to turn on, but it's quickly limited to approximately 1.5 volts by our smart gate drive state machine.
To summarize, the DRV8305-Q1 comes with a smart gate drive, slew-rate control for EMI reduction, start-stop support, SPI configurability and diagnosis, 1, 3, or 6 channel PWM options, 150 degree C ambient operation, three high-performance current sense amps, and an integrated power supply for the MCU. If you'd like additional information, please go to www.ti.com and search for DRV8305-Q1. Thank you for listening, and as always, good luck spinning those motors.

Details

Date:
July 12, 2016

This video introduces the DRV8305-Q1 Automotive 3-Phase Brushless DC Gate Driver. In the video, you will learn about the key features and benefits of the device and how the new Smart Gate Driver Technology can increase the performance in powertrain applications.